Hawk312

iTrader: (8)

My wife`s `98 Trans am is trying to keep itself at 2500 rpms or above, but only when the engine is hot, atleast above 180º. When the engine is cold, it runs perfectly. There is no loss of power, in fact, in runs quite strong. When it starts acting up, I can completely let off the gas in 4th gear and it will maintain speed indefinitely. Slamming down on the gas has no effect, except what you would expect when you slam down on the gas. The engine still drops back down to 2500 rpms or so. Once we let the engine cool down, it runs fine again. It just started doing this. It also seems as though the charge voltage is down, just under 13 volts, when it happens. It also sounds as though the electric fan motors are struggling, which makes me think it is related to that.
Any ideas?
Thanks!

LeftySS

iTrader: (17)

Have you recently done any mods? Sounds like it could be tuning related? Maybe your base running airflow table set way to high in the upper engine temps? It just started happening out of the blue, without any changes being made to the car? Hard to know with given information. Not trying to be a DH just need more information.

Hawk312

iTrader: (8)

Yeah, in fact she just had the engine replaced. However, it was a stock LS1 block with the only changes being an LS6 cam and springs. Other than that, stock from the airbox to the tailpipe.

LeftySS

iTrader: (17)

So did it drive fine once she got the car back? Or has it done this ever since the engine was replaced?

Hawk312

iTrader: (8)

Yeah, the car seems to have been driving great until this. We`ve only had it back since Saturday though. But she has been driving it alot, as she is really excited to have it back.
About the DH thing, no worries. I just appreciate the help.

LeftySS

iTrader: (17)

Hum. Who changed the motor out? Did they do anything to the tune being that there is a different cam. I would think a stock tune on that cam wouldn't do that, but I am not sure. Have you checked all the vaccum lines? I am not sure if the AIR or EGR system could cause something like this or not? Sounds to me like it is something in the tune, a leak somewhere that gets more pronounced as the car heats up, or maybe the IAC is on the fritz. I am racking my brain trying to think. Maybe someone else that has had this happen will chime in. I will keep thinking but kinda at a lost. Sorry.

Hawk312

iTrader: (8)

Could it possibly be the electric fans shorting out and draining the voltage, and the computer is trying to compensate and keep it running by raising the rpms?

Hawk312

iTrader: (8)

Also forgot to mention.....it is hard to start the car just before this happens, sorta like the battery is just about dead. If I have a hard time starting the car, I know it is going to act up, and it does start acting up immediately.

LeftySS

iTrader: (17)

Yeah possibly. Could be your alternator. Was it replaced with the engine? That would be the cause of the battery feeling like it is almost dead.

TooLateVTEC

iTrader: (2)

I would pull the battery and take it somewhere to have it checked.

I was just reading another post last week I think where these cars do wierd **** when the battery is taking a ****.

ZHAWK154

iTrader: (1)

def sounds like a battery / alt issue. did the old engine overheat and die? if fans were bad they would blow fuse